1 missing person found dead after explosion at Wis. corn mill

CAMBRIA, Wis. -- A sheriff says a second person has been killed in a corn mill explosion in southern Wisconsin as crews continue to search the debris for a third person still missing. 

Columbia County Sheriff Dennis Richards confirmed the second death at a news conference Thursday evening. Richards also said the cause of the explosion remains unknown. 

Officials said crews are still searching for the other missing employee, and that the explosion site is still being treated as a search and rescue investigation, not a recovery, CBS affiliate WISC reports.   

The names of the victims have not yet been released.

Richards earlier said that 16 employees were inside the plant in the Village of Cambria when the blast occurred.

The explosion occured at the Didion Milling Corn Mill at 11 p.m. Wednesday night. 

Cambria Fire Chief Cody Doucette also confirmed that a smaller fire occurred in a different part of the plant on Monday. Doucette says investigators are trying to determine if there was a connection between the fires.

The mill was reprimanded by federal safety inspectors six years ago for not taking precautions against dust explosions, which are a major hazard in handling grain, records showed.